Wetting of intake manifold

ABSTRACT

A wetting system for the intake manifold of an automotive internal combustion engine. The system includes an intake manifold and carburetor for delivering a charge to the intake manifold. A device is incorporated for shutting off the flow of fuel during extreme decelerations to reduce the emission of smog producing constituents from the exhaust and nozzles deliver fuel from the accelerating pump to the intake manifold for rewetting the manifold upon reacceleration for promoting smoother operation.

United States Patent m1 3,608;532

[72] Inventor Robert N. Ballutf 3,254,638 6/1966 Walker et al. 123/97 BRives Junction, Mich. 3,437,081 4/1969 Mennesson 261/341 [21] Appl. No.820,134 3,447,516 6/1969 Bartholomew. 123/97 B [22] Filed Apr. 29,19692,291,431 7/1942 Hartz 123/1 19 [45] i Sept 1971 PrimaryExaminerLaurence M. Goodridge [73] Ass'gnee Tenneco Attorney-Harness,Dickey & Pierce Houston, Tex.

[S4] WETTING 0F INTAKE MANIFOLD 1 Claim, 2 Drawing Figs.

[52] U.S.C1. 123/139 AU, ABSTRACT: A wetting System for the intakemanifold of an 123/119 y 123/139 Aw automotive internal combustionengine. The system includes [51] Int. Cl F02m 19/00 an intake if id andcarburetor for delivering a charge m 0 Search B, the intake manifold Adevice is incorporated for hutting off 261/341 the flow of fuel duringextreme decelerations to reduce the emission of smog producingconstituents from the exhaust and References Cited nozzles deliver fuelfrom the accelerating pump to the intake UNITED STAT PATENTS manifoldfor rewetting the manifold upon reacceleration for 3,198,187 8/1965Bartholomew 261/34.1 promoting smoother operation.

s {X}; j l J? 0/]? 4" f E, 2. 1/ *7 l I I L ,7 ,7! i '/4 W WETTING OFINTAKE MANIFOLD BACKGROUND OF THE INVENTION This invention relates to aninternal combustion engine and more particularly to an improved fueldistribution system for such an engine and especially one whichincorporates a structure for rewetting the manifold after extremedecelerations.

In the past few years, considerable work has been done toward reducingthe emission of smog producing constituents from the exhaust gases ofinternal combustion engines. One avenue toward this result hasconcentrated on the improvement of the operating efficiency of theengine. Various arrangements have been proposed for use in connectionwith this approach. One engine-operating condition during which emissionis high is under extreme decelerations. Under such an operatingcondition, the engine acts as a pump and draws raw fuel from the idlecircuits of the carburetor which fuel is not burned and thus is directlydischarged to the atmosphere. It has been proposed, therefore, toprovide some system for shutting off the flow of fuel from thecarburetor to the intake manifold during extreme decelerations. Suchdevices obviously will reduce the emission of unburned hydrocarbonsunder this operating condition. As with many of the smog reducingdevices, such fuel shut off devices adversely affect the engineperformance. Since the fuel discharge circuits of the carburetor arespaced at some distance from the induction ports of the engine, there isa considerable lag in the delivery of fuel to the cylinders uponreacceleration This lag results in hesitation or stumbling in the engineoperation during reacceleration.

In order to cure the aforenoted defect, various devices have beenproposed for admitting additional fuel to the intake manifold duringreacceleration. Such devices are, however, not completely satisfactorysince the additional fuel must still travel the length from thecarburetor to the cylinders. In addition, the devices previouslyproposed for this purpose have been generally complicated and,therefore, costly.

It is, therefore, a principal object of this invention to provide animproved device for rewetting the intake manifold of an internalcombustion engine after deceleration.

It is another object of the invention to provide a simplified manifoldrewetting device.

It is a further object of this invention to provide a manifold rewettingdevice that delivers fuel directly from the carburetor accelerating pumpto the manifold contiguous to the cylinders.

SUMMARY OF THE INVENTION This invention is particularly adapted to beembodied in an automotive internal combustion engine having an inductionmanifold for delivering a charge to a cylinder, a charge forming devicefor delivering a combustible charge to the induction BRIEF DESCRIPTIONOF THE DRAWINGS FIG. 1 is a cross-sectional, partially schematic view ofan internal combustion engine embodying this invention.

FIG. 2 is an enlarged cross-sectional view taken along the line 2-2 ofFIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An internal combustionengine embodying this-invention is illustrated schematically and isidentified generally by the.

reference numeral 11. The engine'll includes one or more cylinders 12,an induction manifold 13 having indiyidualintakepassages or runners 14for each of the cylinders 12 and a carburetor or other charge formingdevice 15 for delivering a combustible charge to the manifold 13. Inaddition, a device of any known type (not shown) is provided forshutting off the flow of fuel from the carburetor 15 to the inductionmanifold 13 upon extreme decelerations. Any of the known fuel shut offdevice normally provided for this purpose may be employed in connectionwith this invention and for this reason such a device has not beenshown. Generally, such devices are responsive to induction system vacuumand operated to stop the flow of fuel to the manifold 13 when manifoldvacuum exceeds a predetermined value. The fuel shutoff may beaccomplished by valves in the idle discharge circuit of the carburetor15, by means of air bleeds or in accordance with any other methodgenerally used for this purpose.

As has been noted, the manifold 13 has separate runners or passages 14that supply a combustible charge to the respective cylinders 12. Theflow of such gases to the cylinders 12 is controlled by means of one ormore poppet valves 16 that are positioned at the mouth of a port 17 inthe cylinder head 18 of the engine.

The carburetor 15 includes a throttle valve 19 that controls the flow ofair and fuel mixture through the carburetor induction passage 21. Fuelis delivered to this induction passage 21 from a fuel bowl 22 via one ormore fuel delivery circuits which may include an idle and a main fuelcircuit (not shown). In addition, the carburetor 15 includes anaccelerating pump, indicated generally by the reference numeral 23. Theaccelerating pump is comprised of a bore 24 in which a piston 25 issupported. The piston is connected to a piston rod 26 that is, in turn,connected in any suitable manner to the throttle linkage (not shown)that serves to actuate the throttle valve 19. When the throttle valve 19closes, the piston 25 is drawn upwardly in the bore 24 to the positionshown in FIG. 1 and fuel is drawn into the bore 24 by means of a passage27 in which a spring-biased ball check valve 28 is interposed. When thethrottle valve 19 is opened rapidly, the piston 25 is driven downwardlyand fuel is driven from the cylinder bore 24 into the carburetorinduction passage 21 through a passage 29, past a check valve 31 and outof a discharge port 32. The construction thus far described isconventional.

As has been noted, the engine 11 includes some form of device forshutting off the flow of fuel from the carburetor 15 to the intakemanifold 13 upon extreme decelerations. As a result, substantially nocombustible mixture will be drawn into the cylinders 12 when the engineis otherwise operating as a pump and the emission of unburnedhydrocarbons from the exhaust gases will be substantially if notcompletely reduced. During this condition, however, any liquid fueldroplets which may have accumulated in the runners 14 will be passedthrough the cylinders 12 leaving the manifold runners 14 completely dryof fuel. When the throttle valve 19 is reopened, there will be a smallbut nevertheless significant time lag before fuel is again transmittedfrom the fuel is again transmitted from the carburetor 15 through therunners 14 to the cylinders 12. Although the accelerating pump 23 willdrive additional fuel into the carburetor induction passage 21 duringthis condition, there will nevertheless be such a time or power lag andperformance of the associated vehicle will be adversely affected.

In order to preclude this unsatisfactory performance characteristic,injection nozzles 33 are provided in each of the manifold runners 14adjacent the valve 16. A conduit 34 extends from each of the injectionnozzles back into a common supply pipe 35 (FIG. 2) that intersects thedischarge nozzle 33 of the accelerating pump 23. Thus, when theaccelerating pump 23 is operated, in addition to delivering supplementalfuel to the carburetor induction passage 21, it will deliver fuel almostdirectly to each of the cylinders 12 through the opened intake valves16. The fuel thus delivered will insure adequate power until the mainfuel supply has had time to pass from the carburetor-15 into therunners14 It should be readily apparent that this arrangement is extremelysimple in construction and requires no complicated modifications to theengine carburetor or induction manifold. In addition, the supplementalfuel required upon reacceleration is admitted almost directly to thecylinders and need not travel the length of the runners 14.

What is claimed is:

1. In an automotive internal combustion engine having an intake manifoldfor delivering a fuel charge to an intake valve, said manifold havingwalls subject to becoming fuel dry upon reacceleration of the automobileand thereby causing lag in engine operation, a charge-forming device fordelivering a combustible charge of fuel and air to the intake manifold.said device including an accelerating pump unit having an outlet passagefor pumped liquid fuel and a charge forming chamber for mixing liquidfuel with air, said outlet passage leading to said'chamber, said pumpincluding a bore and a piston in the bore, said piston having means forconnection to throttle linkage of the engine so the liquid fuel isforced into said outletpassage upon accelerating movement of thethrottle, means forming a second passage intersecting said outletpassage and receiving liquid fuel'thereform, an open conduit connectedat one end to said second passage to receive liquid fuel upon operationof the pump, a nozzle in said intake manifold positioned to spray liquidfuel in said manifold toward said intake valve, the other end of theconduit being connected to and delivering fuel to the nozzle wherebyoperation of the accelerating pump delivers liquid fuel directly to theintake manifold to counteract dry wall and overcome lag in operation ofthe engine.

1. In an automotive internal combustion engine having an intake manifoldfor delivering a fuel charge to an intake valve, said manifold havingwalls subject to becoming fuel dry upon reacceleration of the automobileand thereby causing lag in engine operation, a charge-forming device fordelivering a combustible charge of fuel and air to the intake manifold,said device including an accelerating pump unit having an outlet passagefor pumped liquid fuel and a charge forming chamber for mixing liquidfuel with air, said outlet passage leading to said chamber, said pumpincluding a bore and a piston in the bore, said piston having means forconnection to throttle linkage of the engine so the liquid fuel isforced into said outlet passage upon accelerating movement of thethrottle, means forming a second passage intersecting said outletpassage and receiving liquid fuel therefrom, an open conduit connectedat one end to said second passage to receive liquid fuel upon operationof the pump, a nozzle in said intake manifold positioned to spray liquidfuel in said manifold toward said intake valve, the other end of theconduit being connected to and delivering fuel to the nozzle wherebyoperation of the accelerating pump delivers liquid fuel directly to theintake manifold to counteract dry wall and overcome lag in operation ofthe engine.